U.S. patent application number 16/646805 was filed with the patent office on 2020-07-16 for air conditioner.
The applicant listed for this patent is Mitsubishi Electric Corporation. Invention is credited to Daisuke ITO.
Application Number | 20200224891 16/646805 |
Document ID | / |
Family ID | 66173916 |
Filed Date | 2020-07-16 |
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United States Patent
Application |
20200224891 |
Kind Code |
A1 |
ITO; Daisuke |
July 16, 2020 |
AIR CONDITIONER
Abstract
An air conditioner includes a casing, and a blower and a
refrigerant circuit disposed in the casing. The blower is
configured to blow air. The refrigerant circuit has a compressor, a
condenser, a decompressor, and an evaporator and is configured to
circulate refrigerant in order of the compressor, the condenser,
the decompressor, and the evaporator. The condenser has a first
heat transfer tube through which the refrigerant flows and which
has a first outside diameter. The evaporator has a second heat
transfer tube through which the refrigerant flows and which has a
second outside diameter. The evaporator is disposed windward of the
condenser. The first outside diameter of the first heat transfer
tube of the condenser is smaller than the second outside diameter
of the second heat transfer tube of the evaporator.
Inventors: |
ITO; Daisuke; (Tokyo,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Mitsubishi Electric Corporation |
Tokyo |
|
JP |
|
|
Family ID: |
66173916 |
Appl. No.: |
16/646805 |
Filed: |
October 20, 2017 |
PCT Filed: |
October 20, 2017 |
PCT NO: |
PCT/JP2017/038027 |
371 Date: |
March 12, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F24F 13/222 20130101;
F25B 29/00 20130101; F24F 1/029 20190201; F24F 1/028 20190201; F24F
1/02 20130101; F24F 1/022 20130101 |
International
Class: |
F24F 1/022 20060101
F24F001/022; F24F 1/028 20060101 F24F001/028; F24F 1/029 20060101
F24F001/029; F24F 13/22 20060101 F24F013/22 |
Claims
1. An air conditioner comprising: a casing; and a blower and a
refrigerant circuit disposed in the casing, wherein the blower is
configured to blow air, the refrigerant circuit has a compressor, a
condenser, a decompressor, and an evaporator and is configured to
circulate refrigerant in order of the compressor, the condenser,
the decompressor, and the evaporator, the condenser has a first
heat transfer tube through which the refrigerant flows and which
has a first outside diameter, the evaporator has a second heat
transfer tube through which the refrigerant flows and which has a
second outside diameter, the evaporator is disposed windward of the
condenser, and the first outside diameter of the first heat
transfer tube of the condenser is smaller than the second outside
diameter of the second heat transfer tube of the evaporator.
2. The air conditioner according to claim 1, wherein a material for
the condenser has a pitting potential higher than a pitting
potential of a material for the evaporator.
3. The air conditioner according to claim 1, wherein the second
heat transfer tube of the evaporator is a circular tube, the first
heat transfer tube of the condenser is a flat tube, and the first
heat transfer tube has a cross-section that extends in a direction
in which the evaporator and the condenser are aligned.
4. The air conditioner according to claim 3, wherein the first heat
transfer tube of the condenser is disposed in a region which is
less occupied by the second heat transfer tube of the evaporator in
the direction in which the evaporator and the condenser are
aligned.
5. The air conditioner according to claim 1, wherein the
refrigerant is a hydrocarbon-based flammable refrigerant, and a
capacity of the condenser to a capacity of the evaporator is 100%
or less.
6. The air conditioner according to claim 1, wherein each of the
condenser and the evaporator has an area larger than an area of a
suction port of the blower.
7. The air conditioner according to claim 6, wherein a clearance is
provided between the condenser and the suction port of the
blower.
8. The air conditioner according to claim 1, comprising a drain pan
disposed below the condenser, wherein a clearance is provided
between the condenser and the drain pan.
Description
TECHNICAL FIELD
[0001] The present invention relates to air conditioners.
BACKGROUND ART
[0002] An example air conditioner is a dehumidifying apparatus. The
dehumidifying apparatus is disclosed in, for example, Japanese
Patent Laying-Open No. 2001-221458 (PTL 1). In the dehumidifying
apparatus described in PTL 1, an evaporator is disposed windward of
a condenser. In a common dehumidifying apparatus, the outside
diameter of a heat transfer tube in the evaporator is equal to the
outside diameter of a heat transfer tube in the condenser.
CITATION LIST
Patent Literature
[0003] PTL 1: Japanese Patent Laying-Open No. 2001-221458
SUMMARY OF INVENTION
Technical Problem
[0004] When the outside diameter of the heat transfer tube in the
evaporator is equal to the outside diameter of the heat transfer
tube in the condenser, the ventilation resistance of a flow path of
air that flows around the heat transfer tube in the evaporator is
maintained in a flow path of air that flows around the heat
transfer tube in the condenser. Thus, the ventilation resistance of
the flow path of the air that flows around the heat transfer tube
in the condenser may not be smaller than the ventilation resistance
of the flow path of air that flows around the heat transfer tube in
the evaporator.
[0005] The present invention has been made in view of the above
problem, and has an object to provide an air conditioner capable of
causing the ventilation resistance of a flow path of air that flows
around a heat transfer tube in a condenser to be smaller than the
ventilation resistance of a flow path of air that flows around a
heat transfer tube in an evaporator.
Solution to Problem
[0006] An air conditioner according to the present invention
includes a casing, and a blower and a refrigerant circuit disposed
in the casing. The blower is configured to blow air. The
refrigerant circuit has a compressor, a condenser, a decompressor,
and an evaporator and is configured to circulate refrigerant in
order of the compressor, the condenser, the decompressor, and the
evaporator. The condenser has a first heat transfer tube through
which the refrigerant flows and which has a first outside diameter.
The evaporator has a second heat transfer tube through which the
refrigerant flows and which has a second outside diameter. The
evaporator is disposed windward of the condenser. The first outside
diameter of the first heat transfer tube of the condenser is
smaller than the second outside diameter of the second heat
transfer tube of the evaporator.
Advantageous Effects of Invention
[0007] In the present invention, since the first outside diameter
of the first heat transfer tube of the condenser is smaller than
the second outside diameter of the second heat transfer tube of the
evaporator disposed windward of the condenser, the ventilation
resistance of the flow path of air that flows around the first heat
transfer tube in the condenser can be made smaller than the
ventilation resistance of the flow path of air that flows around
the second heat transfer tube in the evaporator.
BRIEF DESCRIPTION OF DRAWINGS
[0008] FIG. 1 shows a refrigerant circuit of a dehumidifying
apparatus according to Embodiment 1 of the present invention.
[0009] FIG. 2 schematically shows a configuration of the
dehumidifying apparatus according to Embodiment 1 of the present
invention.
[0010] FIG. 3 shows cross-sections of an evaporator and a condenser
of the dehumidifying apparatus according to Embodiment 1 of the
present invention.
[0011] FIG. 4 shows cross-sections of an evaporator and a condenser
of a dehumidifying apparatus according to Embodiment 3 of the
present invention.
[0012] FIG. 5 shows cross-sections of an evaporator and a condenser
of a dehumidifying apparatus according to Embodiment 4 of the
present invention.
[0013] FIG. 6 shows cross-sections of an evaporator and a condenser
of a dehumidifying apparatus according to a comparative example of
Embodiment 4 of the present invention.
[0014] FIG. 7 is a graph showing a relationship between a ratio of
a capacity of a condenser to a capacity of an evaporator and an
amount of refrigerant during change in the capacity of the
condenser to a capacity of the evaporator/an amount of refrigerant
at a combustion lower limit concentration in a dehumidifying
apparatus according to Embodiment 5 of the present invention.
[0015] FIG. 8 shows a positional relationship between an evaporator
and a suction port of a blower of a dehumidifying apparatus
according to Embodiment 6 of the present invention.
[0016] FIG. 9 schematically shows a configuration of a
dehumidifying apparatus according to Embodiment 7 of the present
invention.
[0017] FIG. 10 shows cross-sections of an evaporator and a
condenser of a dehumidifying apparatus according to Embodiment 8 of
the present invention.
DESCRIPTION OF EMBODIMENTS
[0018] Embodiments of the present invention will now be described
in detail with reference to the drawings. The same or corresponding
parts are designated by the same references, description of which
will not be repeated. Each of the embodiments will describe a
dehumidifying apparatus as an example air conditioner.
Embodiment 1
[0019] A configuration of a dehumidifying apparatus 1, which is an
air conditioner according to Embodiment 1 of the present invention,
will be described with reference to FIGS. 1 and 2. FIG. 1 shows a
refrigerant circuit of dehumidifying apparatus 1 according to
Embodiment 1 of the present invention. FIG. 2 schematically shows a
configuration of dehumidifying apparatus 1 according to Embodiment
1 of the present invention.
[0020] As shown in FIGS. 1 and 2, dehumidifying apparatus 1
includes a refrigerant circuit 10, which has a compressor 2, a
condenser 3, a decompressor 4, and an evaporator 5, a blower 6, and
a casing 20. Refrigerant circuit 10 and blower 6 are disposed in
casing 20. Casing 20 faces the external space (indoor space) to be
dehumidified by dehumidifying apparatus 1.
[0021] Refrigerant circuit 10 is configured to circulate
refrigerant in order of compressor 2, condenser 3, decompressor 4,
and evaporator 5. Specifically, refrigerant circuit 10 is composed
of compressor 2, condenser 3, decompressor 4, and evaporator 5
connected in order by a pipe. Refrigerant flows through the pipe
and circulates through refrigerant circuit 10 in order of
compressor 2, condenser 3, decompressor 4, and evaporator 5.
[0022] Compressor 2 is configured to compress refrigerant.
Specifically, compressor 2 is configured to suction low-pressure
refrigerant through a suction port and compress the refrigerant and
then discharge the compressed refrigerant as high-pressure
refrigerant through a discharge port. Compressor 2 may be
configured to have a variable refrigerant discharge displacement.
Specifically, compressor 2 may be an inverter compressor. When
compressor 2 is configured to have a variable refrigerant discharge
displacement, an amount of the refrigerant circulating through
dehumidifying apparatus 1 can be controlled by adjusting the
discharge displacement of compressor 2.
[0023] Condenser 3 is configured to condense the refrigerant having
a pressure increased by compressor 2, thereby cooling the
refrigerant. Condenser 3 is a heat exchanger that performs heat
exchange between refrigerant and air. Condenser 3 has a refrigerant
inlet and a refrigerant outlet, and an air inlet and an air outlet.
The refrigerant inlet of condenser 3 is connected to the discharge
port of compressor 2 by a pipe.
[0024] Decompressor 4 is configured to decompress the refrigerant
cooled by condenser 3 to expand the refrigerant. Decompressor 4 is,
for example, an expansion valve. This expansion valve may be an
electronic control valve. Decompressor 4 is not limited to the
expansion valve and may be a capillary tube. Decompressor 4 is
connected to each of the refrigerant outlet of condenser 3 and the
refrigerant inlet in evaporator 5 by a pipe.
[0025] Evaporator 5 is configured to cause the refrigerant expanded
by decompression in decompressor 4 to absorb heat, thereby
evaporating the refrigerant. Evaporator 5 is a heat exchanger that
performs heat exchange between refrigerant and air. Evaporator 5
has a refrigerant inlet and a refrigerant outlet, and an air inlet
and an air outlet. The refrigerant outlet of evaporator 5 is
connected to the suction port of compressor 2 by a pipe. Evaporator
5 is disposed upstream of condenser 3 in an airflow generated by
blower 6. In other words, evaporator 5 is disposed windward of
condenser 3.
[0026] Blower 6 is configured to blow air. Blower 6 is configured
to take in air from the outside to the inside of casing 20 and blow
the air to condenser 3 and evaporator 5. Specifically, blower 6 is
configured to take in air from the external space (indoor space)
into casing 20 and cause the air to flow through evaporator 5 and
condenser 3, and then discharge the air to the outside of casing
20.
[0027] In the present embodiment, blower 6 has a shaft 6a and a fan
6b that rotates about shaft 6a. As fan 6b rotates about shaft 6a,
the air taken in from the external space (indoor space) as
indicated by an arrow A in the figure flows through evaporator 5
and condenser 3 in order, and is then discharged to the external
space (indoor space) again as indicated by an arrow B in the
figure. In this manner, air circulates through the external space
(indoor space) via dehumidifying apparatus 1.
[0028] In the present embodiment, blower 6 is disposed downstream
of condenser 3 in the airflow generated by blower 6. Blower 6 may
be disposed between condenser 3 and evaporator 5 or upstream of
evaporator 5 in the airflow generated by blower 6. For example, one
blower 6 may be provided.
[0029] Casing 20 is provided with an air inlet 21 for taking in air
to the inside of casing 20 from the external space (indoor space)
to be dehumidified and an air outlet 22 for blowing out air to the
external space (indoor space) from the inside of casing 20. Casing
20 also has an air path (flow path of air) 23 connecting air inlet
21 to air outlet 22. Evaporator 5, condenser 3, and blower 6 are
disposed in air path 23. Evaporator 5 and condenser 3 are thus
disposed in the same air path 23.
[0030] As fan 6b rotates about shaft 6a in air path 23 as indicated
by an arrow C in the figure, air suctioned from the outside of
casing 20 through air inlet 21 to the inside of casing 20 flows
through evaporator 5, condenser 3, and blower 6 in order, and is
then flowed through air outlet 22 to the outside of casing 20.
[0031] In dehumidifying apparatus 1, any member which constitutes
the refrigerant circuit together with condenser 3, evaporator 5,
and blower 6 may be disposed in air path 23. For example,
decompressor 4 may be disposed in air path 23.
[0032] Casing 20 also includes a partition 24 that partitions air
path 23 into a first region 23a and a second region 23b. In other
words, two regions, first region 23a and second region 23b
partitioned by partition 24, are provided in casing 20. Condenser 3
and evaporator 5 are disposed in first region 23a. Blower 6 is
disposed in second region 23b. First region 23a is located windward
of second region 23b in the airflow generated by blower 6.
[0033] Referring to FIG. 2, partition 24 has a suction port 24a of
blower 6 which is configured to connect first region 23a to second
region 23b. Partition 24 is formed as a flat plate, for example.
When suction port 24a is seen from first region 23a in the
direction (axial direction) in which shaft 6a of blower 6 extends,
fan 6b is disposed in suction port 24a. In other words, the outside
diameter of fan 6b is smaller than the inside diameter of suction
port 24a. Suction port 24a is configured not to block the suction
area of fan 6b.
[0034] When the air conditioner is installed in a room, the room
may be cooled by the dissipation of heat of condenser 3 to the
outside of the room. For such heat dissipation, an exhaust duct may
be mounted on a device on the window side, or the device itself may
be installed on the window side.
[0035] Configurations of condenser 3 and evaporator 5 will now be
described in detail with reference to FIG. 3. FIG. 3 shows
cross-sections of condenser 3 and evaporator 5 according to
Embodiment 1 of the present invention.
[0036] In dehumidifying apparatus 1 of the present embodiment,
condenser 3 has a plurality of fins 11 and a first heat transfer
tube 12. Each of fins 11 is formed as a thin plate. Fins 11 are
disposed to be stacked on one another. First heat transfer tube 12
is disposed to pass through fins 11 stacked on one another in a
stack direction. First heat transfer tube 12 has a plurality of
first linear portions extending linearly in the stack direction and
a plurality of first curved portions connecting the plurality of
first linear portions. Each of the plurality of first linear
portions and a corresponding one of the plurality of first curved
portions are connected to each other, resulting in first heat
transfer tube 12 configured in a meandering manner. In the present
embodiment, first heat transfer tube 12 is a circular tube.
[0037] Evaporator 5 has a plurality of fins 13 and a second heat
transfer tube 14. Each of fins 13 is formed as a thin plate. Fins
13 are disposed to be stacked on one another. Second heat transfer
tube 14 is disposed to pass through fins 13 stacked on one another
in a stack direction. Second heat transfer tube 14 has a plurality
of second linear portions extending linearly in the stack direction
and a plurality of second curved portions connecting the plurality
of second linear portions. Each of the plurality of second linear
portions and a corresponding one of the plurality of second linear
portions are connected to each other in series, resulting in second
heat transfer tube 14 configured in a meandering manner. In the
present embodiment, second heat transfer tube 14 is a circular
tube.
[0038] FIG. 3 shows cross-sections of condenser 3 and the
evaporator, which are orthogonal to the stack direction of fins 11
of condenser 3 and the stack direction of fins 13 of the
evaporator, respectively. In condenser 3, the first linear portions
of first heat transfer tube 12 are disposed in the cross-section
shown in FIG. 3. The first linear portions of first heat transfer
tube 12 have an equal outside diameter (first outside diameter) and
an equal inside diameter (first inside diameter).
[0039] In the present embodiment, the first linear portions of
first heat transfer tube 12 are disposed side by side in three rows
in a row direction. The intervals between the first linear portions
of first heat transfer tube 12 which are disposed in the respective
rows in the row direction may be equal to each other. This interval
is a distance between the centers of the first linear portions of
first heat transfer tube 12 which are disposed in the respective
rows adjacent to each other in the row direction. In the present
embodiment, the first linear portions of first heat transfer tube
12 in the respective rows adjacent to each other in the row
direction are disposed so as not to be aligned in a stage
direction. In other words, the centers of the first linear portions
of first heat transfer tube 12 in the respective rows adjacent to
each other in the row direction are not disposed linearly in the
row direction.
[0040] In the present embodiment, also, the first linear portions
of first heat transfer tube 12 in the respective rows adjacent to
each other in the row direction are disposed so as not to overlap
each other in the row direction. In the present embodiment,
further, the first linear portions of first heat transfer tube 12
in the respective rows adjacent to each other in the row direction
are disposed so as not to partially overlap each other in the stage
direction.
[0041] In the present embodiment, the first linear portions of
first heat transfer tube 12 are disposed side by side in four
stages in the stage direction in each row. In the present
embodiment, also, the first linear portions of first heat transfer
tube 12 are disposed linearly side by side in the stage direction
in each row. In other words, the centers of the first linear
portions of first heat transfer tube 12 which are disposed side by
side in the stage direction in each row are disposed in a line. In
the present embodiment, further, the first linear portions of first
heat transfer tube 12 which are disposed in the respective rows at
the opposite ends in the row direction of the three rows are
located at the same position in the stage direction. The positions
in the stage direction of the first linear portions of first heat
transfer tube 12 which are disposed in the center row in the row
direction of the three rows are located at the center between the
positions in the stage direction of the first linear portions of
first heat transfer tube 12 which are disposed in the respective
rows at the opposite ends.
[0042] In evaporator 5, the second linear portions of second heat
transfer tube 14 are disposed in the cross-section shown in FIG. 3.
The second linear portions of second heat transfer tube 14 may have
an equal outside diameter (second outside diameter) and an equal
inside diameter (second inside diameter).
[0043] In the present embodiment, the second linear portions of
second heat transfer tube 14 are disposed side by side in three
rows in the row direction. The intervals between the second linear
portions of second heat transfer tube 14 which are disposed in the
respective rows in the row direction of the three rows may be equal
to each other. This interval is a distance between the centers of
the second linear portions of second heat transfer tube 14 which
are disposed in the respective rows adjacent to each other in the
row direction. In the present embodiment, the second linear
portions of second heat transfer tube 14 in the respective rows
adjacent to each other in the row direction are disposed so as not
to be aligned in the stage direction. In other words, the centers
of the second linear portions of second heat transfer tube 14 in
the respective rows adjacent to each other in the row direction are
not disposed linearly in the row direction.
[0044] In the present embodiment, also, the second linear portions
of second heat transfer tube 14 in the respective rows adjacent to
each other in the row direction are disposed to partially overlap
each other in the row direction. In the present embodiment,
further, second heat transfer tubes 14 in the respective rows
adjacent to each other in the row direction are disposed to
partially overlap each other in the stage direction.
[0045] In the present embodiment, the second linear portions of
second heat transfer tube 14 are disposed side by side in four
stages in the stage direction in each row. In the present
embodiment, also, the second linear portions of second heat
transfer tube 14 are disposed linearly side by side in the stage
direction in each row. In other words, the centers of the second
linear portions of second heat transfer tube 14 which are disposed
side by side in the stage direction in each row are disposed in a
line. In the present embodiment, further, the second linear
portions of second heat transfer tube 14 which are disposed in the
respective rows at the opposite ends in the row direction of the
three rows are located at the same position in the stage direction.
The positions in the stage direction of the second linear portions
of second heat transfer tube 14 which are disposed in the center
row in the row direction of the three rows are located at the
center between the positions in the stage direction of the second
linear portions of second heat transfer tube 14 which are disposed
in the respective rows at the opposite ends.
[0046] The first outside diameter of first heat transfer tube 12 of
condenser 3 is smaller than the second outside diameter of second
heat transfer tube 14 of evaporator 5. The first inside diameter of
first heat transfer tube 12 of condenser 3 is smaller than the
second inside diameter of second heat transfer tube 14 of
evaporator 5. The positions of the centers of the first linear
portions of first heat transfer tube 12 which are disposed in the
respective rows at the opposite ends in the row direction of three
rows in condenser 3 are the same in the stage direction as the
positions of the centers of the second linear portions of second
heat transfer tube 14 which are disposed in the central row in the
row direction of the three rows in evaporator 5. The positions of
the centers of first linear portions of first heat transfer tube 12
which are disposed in the central row in the row direction of three
rows in condenser 3 are the same in the stage direction as the
positions of the centers of the second linear portions of second
heat transfer tube 14 which are disposed in the respective rows at
the opposite ends in the row direction of three rows in evaporator
5.
[0047] The shortest distance between the adjacent first linear
portions in first heat transfer tube 12 is greater than the
shortest distance between the adjacent second linear portions of
second heat transfer tube 14. This shortest distance is the
shortest distance between the outer circumferential surfaces of the
adjacent heat transfer tubes. The width of the flow path of air
that flows around first heat transfer tube 12 is thus greater than
the width of the flow path of air that flows around second heat
transfer tube 14. For this reason, the ventilation resistance of
the flow path of air that flows around first heat transfer tube 12
is smaller than the ventilation resistance of the flow path of air
that flows around second heat transfer tube 14.
[0048] In FIG. 3, condenser 3 and evaporator 5 are disposed in
parallel in the row direction (horizontal direction).
Alternatively, condenser 3 and evaporator 5 may be disposed in
parallel in the stage direction (vertical direction). For example,
even when condenser 3 is located on the upper side and evaporator 5
is located on the lower side, it suffices that evaporator 5 is
located on the windward side, condenser 3 is located on the leeward
side, and condenser 3 and evaporator 5 are installed in the same
air path. First heat transfer tube 12 and second heat transfer tube
14 are not limited to circular tubes, and it suffices that when the
tube sectional area of the heat transfer tube through which
refrigerant flows is converted into the corresponding sectional
area of the circular tube, the corresponding diameter of the heat
transfer tube of condenser 3 is smaller than the corresponding
diameter of the heat transfer tube of evaporator 5. The
corresponding diameter is defined by (4.times.tube sectional
area/.pi.){circumflex over ( )}0.5.
[0049] The operation of dehumidifying apparatus 1 during
dehumidification operation will now be described with reference to
FIGS. 1 and 2.
[0050] Refrigerant in the form of superheated gas discharged from
compressor 2 flows into condenser 3 disposed in air path 23. The
refrigerant in the form of superheated gas which has flowed into
condenser 3 is subjected to heat exchange with air, which has been
taken in from the external space into air path 23 through air inlet
21, to be cooled, thereby turning into gas-liquid two-phase state
refrigerant. The gas-liquid two-phase state refrigerant is cooled
further to turn into supercooled refrigerant.
[0051] The refrigerant in the form of supercooled liquid which has
flowed from condenser 3 flows through decompressor 4 to be
decompressed, turns into gas-liquid two-phase state refrigerant,
and then flows into evaporator 5 disposed in air path 23. The
gas-liquid two-phase state refrigerant which has flowed into
evaporator 5 is subjected to heat exchange with air taken into air
path 23 from the external space through air inlet 21 to be heated,
turning into refrigerant in the form of superheated gas. The
refrigerant in the form of superheated gas is suctioned by
compressor 2 and compressed in compressor 2, and is discharged
again.
[0052] The functions and effects of the present embodiment will now
be described.
[0053] In dehumidifying apparatus 1 according to the present
embodiment, since the first outside diameter of first heat transfer
tube 12 of condenser 3 is smaller than the second outside diameter
of second heat transfer tube 14 of evaporator 5 disposed windward
of condenser 3, the width of the flow path of air in condenser 3 is
greater than the width of the flow path of air in evaporator 5. The
ventilation resistance of the flow path of air that flows around
first heat transfer tube 12 in condenser 3 can thus be smaller than
the ventilation resistance of the flow path of air that flows
around second heat transfer tube 14 in evaporator 5. Thus, an input
of blower 6 (fan input) can be reduced by reducing ventilation
resistance. Consequently, dehumidifying apparatus 1 with high
energy saving performance can be provided.
[0054] Also, since the outside diameter of first heat transfer tube
12 of condenser 3 is smaller than the outside diameter of second
heat transfer tube 14 of evaporator 5, the internal capacity of
condenser 3 can be made smaller than the internal capacity of
evaporator 5. This can reduce a required amount of refrigerant to
desired evaporation capability. Further, product cost can be
reduced by reducing an amount of refrigerant.
[0055] The velocity of flow of liquid refrigerant, heat transfer of
which is poor in condenser 3, can be increased by reducing the
diameter of first heat transfer tube 12 of condenser 3, thereby
improving a heat transfer rate. This can improve the heat exchange
performance of condenser 3. Since the velocity of flow of
refrigerant can be increased by causing the number of branches of
the heat transfer tube in the gas refrigerant region or gas-liquid
two-phase refrigerant region to be smaller than the number of
branches of the heat transfer tube in the liquid refrigerant
region, condensation performance can be improved further. Since a
difference between condensation pressure and evaporation pressure
in the refrigerant circuit can be reduced by improving condensation
performance, a workload of compressor 2 can be reduced. This can
reduce power consumption of compressor 2.
Embodiment 2
[0056] Dehumidifying apparatus 1 of Embodiment 2 of the present
invention differs from dehumidifying apparatus 1 of Embodiment 1 in
that a material having a pitting potential higher than that of
evaporator 5 is used for condenser 3. In dehumidifying apparatus 1
of the present embodiment, the material for condenser 3 has a
pitting potential higher than the pitting potential of the material
for evaporator 5.
[0057] Commonly, a material having a lower pitting potential is
more prone to corrosion. At a pitting potential of the material for
condenser 3 which is higher than the pitting potential of the
material for evaporator 5, the corrosion of condenser 3 is reduced
when water (dehumidification water) generated after
dehumidification by evaporator 5 is scattered to condenser 3.
[0058] At a pitting potential of the material for condenser 3 which
is lower than the pitting potential of the material for evaporator
5, the corrosion of the material for condenser 3 is more likely to
progress when the dehumidification water containing the material
for evaporator 5 is scattered to the condenser or when evaporator 5
and condenser 3 contact each other.
[0059] During operation of dehumidifying apparatus 1, condenser 3
has a pressure higher than that of evaporator 5. Condenser 3 is
thus more prone to breakage than evaporator 5 as the corrosion,
particularly pitting progresses, leading to a higher risk of
leakage of refrigerant from condenser 3. For example, when the
materials for evaporator 5 and condenser 3 are aluminum, a
preferable combination of materials is an aluminum alloy 1050
(pitting potential of -745.8 mV) for evaporator 5 and an aluminum
alloy 3003 (pitting potential of -719.3 mV) for condenser 3.
[0060] Since the risk of leakage of refrigerant does not increase
even when fin 13 of condenser 3 corrodes, it suffices that the
pitting potential of the material for first heat transfer tube 12
of condenser 3 is higher than the pitting potential of the material
for second heat transfer tube 14 of evaporator 5. The effect of
preventing leakage of refrigerant due to corrosion of the heat
transfer tube is enhanced by setting pitting potentials such that
the fin of the evaporator.ltoreq.the fin of the condenser<the
heat transfer tube of the evaporator<the heat transfer tube of
the condenser.
[0061] In the air conditioner according to the present embodiment,
the pitting potential of the material for condenser 3 is higher
than the pitting potential of the material for evaporator 5. Thus,
even when the water generated after dehumidification by evaporator
5 is scattered to condenser 3, the corrosion of condenser 3 can be
reduced because condenser 3 is more resistant to corrosion than
evaporator 5.
Embodiment 3
[0062] Referring to FIG. 4, dehumidifying apparatus 1 of Embodiment
3 of the present invention differs from dehumidifying apparatus 1
of Embodiment 1 in first heat transfer tube 12 of condenser 3. FIG.
4 shows cross-sections of condenser 3 and the evaporator, which are
orthogonal to the stack direction of fins 11 of condenser 3 and the
stack direction of fins 13 of the evaporator, respectively.
[0063] Second heat transfer tube 14 of evaporator 5 is a circular
tube. First heat transfer tube 12 of condenser 3 is a flat tube.
First heat transfer tube 12 has a cross-section that extends in the
direction in which evaporator 5 and condenser 3 are aligned. First
heat transfer tube 12 has a plurality of first linear portions
extending linearly in the stack direction and a header connecting
the plurality of first linear portions. Each of the plurality of
first linear portions of first heat transfer tube 12 has a
plurality of small-diameter pipe paths.
[0064] In dehumidifying apparatus 1 according to the present
embodiment, a circular tube having excellent drainage performance
is used as second heat transfer tube 14 of evaporator 5, and a flat
tube which has a small inside diameter and has a flat shape in its
entirety is used as first heat transfer tube 12 of condenser 3.
This can lead to a small ventilation resistance of condenser 3.
[0065] In evaporator 5 of dehumidifying apparatus 1, any
dehumidification water accumulated in fin 13 or second heat
transfer tube 14 may inhibit heat transfer between air and
refrigerant or deteriorate a ventilation resistance. Particularly
in dehumidifying apparatus 1 installed in a room, leakage of
dehumidification water into the room may be caused. A heat
exchanger having a combination of a plate fin and a circular tube
has excellent drainage performance compared with a heat exchanger
including a flat tube or the like, and accordingly can restrain a
decrease in heat exchange performance due to the accumulation of
dehumidification water, because dehumidification water is drained
along the plate fin from the opposite sides in the radial direction
of the circular tube. On the other hand, the use of a heat
exchanger including a flat tube in condenser 3 can reduce the
internal capacity of condenser 3 owing to decreased diameter and
can also reduce a ventilation resistance owing to a flat shape.
[0066] Although the internal capacity can be reduced by using a
plurality of small-diameter circular tubes, a large number of
small-diameter circular tubes are needed to compensate for heat
exchange performance (tube outer area), leading to increases in
ventilation resistance and cost. Since a flat tube with many holes
has a plurality of flow paths integrated into one, the flat tube
can be fewer than small-diameter tubes. Thus, fan input can be
reduced owing to a decreased ventilation resistance, and condenser
3 can be made inexpensively.
[0067] A flat tube may be disposed horizontally or vertically. The
shape of the fin of condenser 3, such as plate fin or corrugated
fin, is selected depending on desired performance, the installation
position of a flat tube, or the like. Thus, dehumidifying apparatus
1 which has excellent energy saving performance and is inexpensive
can be provided.
Embodiment 4
[0068] Referring to FIG. 5, dehumidifying apparatus 1 of Embodiment
4 of the present invention differs from dehumidifying apparatus 1
of Embodiment 1 in first heat transfer tube 12 of condenser 3.
FIGS. 5 and 6 each show cross-sections of condenser 3 and the
evaporator, which are orthogonal to the stack direction of fins 11
and the stack direction of fins 13, respectively.
[0069] As indicated by the arrows in FIG. 5, first heat transfer
tube 12 of condenser 3 is disposed in a region which is less
occupied by second heat transfer tube 14 of evaporator 5 in the
ventilation direction. First heat transfer tube 12 of condenser 3
is disposed in a region which is less occupied by second heat
transfer tube 14 of evaporator 5 in the direction in which
evaporator 5 and condenser 3 are aligned.
[0070] As shown in FIG. 5, since first heat transfer tube 12 of
condenser 3 is disposed in the region which is less occupied by
second heat transfer tube 14 of evaporator 5 in the ventilation
direction (row direction), the ventilation resistance in the
ventilation direction can be made uniform in the stage direction.
This can make the wind velocity distribution of air which enters
evaporator 5 on the most upstream side uniform, leading to high
heat exchange efficiency.
[0071] Since wind velocity increases partially when a drift occurs
in the air of evaporator 5, the ventilation resistance
deteriorates, leading to deteriorated fan input. Since the average
wind velocity on the front surface of the evaporator decreases when
the wind velocity is uniform, fan input can be reduced.
[0072] As shown in FIG. 6, first heat transfer tube 12 of condenser
3 is disposed in the region which is more occupied by second heat
transfer tube 14 of evaporator 5 in the direction in which
evaporator 5 and condenser 3 are aligned. In this case, the tailing
edge of second heat transfer tube 14 of evaporator 5 is a dead
water region with a small heat exchange amount, leading to
deteriorated heat exchange efficiency at the leading edge of first
heat transfer tube 12 of condenser 3.
[0073] Contrastingly, in dehumidifying apparatus 1 according to the
present embodiment, first heat transfer tube 12 of condenser 3 is
disposed in a region which is less occupied by second heat transfer
tube 14 of evaporator 5, as shown in FIG. 5. Thus, air passes
through first heat transfer tube 12 of condenser 3 with the tailing
edge of the second heat transfer tube of evaporator 5 having little
effect. This enables heat transfer at the leading edge of first
heat transfer tube 12 of condenser 3, leading to increased heat
exchange efficiency.
Embodiment 5
[0074] In dehumidifying apparatus 1 of Embodiment 5 of the present
invention, refrigerant may be a hydrocarbon (HC)-based flammable
refrigerant. Specifically, refrigerant may be R290 or the like. The
capacity of condenser 3 to the capacity of evaporator 5 is 100% or
less.
[0075] Referring to FIG. 7, refrigerant will be described by taking
R290, which is a hydrocarbon (HC)-based flammable refrigerant, as
an example. FIG. 7 shows a relationship between a ratio of the
capacity of a condenser to the capacity of evaporator 5 which
represents a capacity of a flow path of refrigerant and an amount
of refrigerant during change in the capacity of condenser 3 to the
capacity of the evaporator/an amount of refrigerant at a combustion
lower limit concentration. At the horizontal axis in FIG. 7, the
ratio of the capacity of the condenser to the capacity of the
evaporator is 100% when the capacity of the evaporator is equal to
the capacity of the condenser. At the vertical axis in FIG. 7, an
amount of refrigerant during change in the capacity of a condenser
to the capacity of an evaporator/an amount of refrigerant at a
combustion lower limit concentration is 100% when an amount of
refrigerant at the combustion lower limit concentration is equal to
an amount of refrigerant during change in the capacity of a
condenser to the capacity of an evaporator. A ratio less than 100%
results in an amount of refrigerant which is nonflammable.
[0076] In an existing heat exchanger including a plate-fin-type
circular tube, the ratio of the capacity of a condenser to the
capacity of an evaporator is 200% or more, which exceeds the ratio
at the combustion lower limit concentration. Dehumidifying
apparatus 1 that can be used at an amount of refrigerant less than
an amount at the combustion lower limit concentration of R290 can
be provided by using a small-diameter circular tube, a flat tube,
or the like as the heat transfer tube of condenser 3 to set the
capacity of condenser 3 to 100% or less with respect to the
capacity of evaporator 5. Since the size of a room for installation
is larger as capability increases, when the ratio of the capacity
of a condenser to the capacity of an evaporator is 100% or less, a
concentration less than the concentration at the combustion lower
limit can be maintained irrespective of capability range. The
combustion lower limit concentration of R290 is 2%, and in the
present embodiment, dehumidifying apparatus 1 can be configured
with a refrigerant amount of less than 2% to the indoor
capacity.
[0077] Although description has been given of refrigerant by taking
R290 as an example, the present invention is not limited thereto.
Although a difference in liquid concentration due to a difference
in another hydrocarbon (HC)-based refrigerant, such as R600a, is
small, the capacity of condenser 3 may be adjusted in accordance
with desired refrigerant.
Embodiment 6
[0078] FIG. 8 shows a positional relationship between evaporator 5
and suction port 24a when evaporator 5 is seen from the side
opposite to suction port 24a in the direction in which evaporator 5
and suction port 24a overlap each other. Referring to FIG. 8, in
dehumidifying apparatus 1 of Embodiment 6 of the present invention,
a heat exchange area by fins and a heat transfer tube is larger
than an area formed by suction port 24a of blower 6. In other
words, the area of each of condenser 3 and evaporator 5 is larger
than the area of suction port 24a of blower 6.
[0079] In dehumidifying apparatus 1 according to the present
embodiment, since the area of each of condenser 3 and evaporator 5
is larger than the area of suction port 24a of blower 6, the wind
velocity of air that flows into condenser 3 and evaporator 5 can be
made smaller than when the area of each of condenser 3 and
evaporator 5 is smaller than the area of suction port 24a of blower
6. This can reduce a ventilation resistance, leading to a reduction
in fan input.
Embodiment 7
[0080] Referring to FIG. 9, a desired clearance t is provided
between condenser 3 and suction port 24a of blower 6 in
dehumidifying apparatus 1 of Embodiment 7 of the present
invention.
[0081] According to the present embodiment, since clearance t is
provided between condenser 3 and suction port 24a of blower 6, air
that flows through condenser 3 and evaporator 5 can be collected in
a wide range beyond the area of suction port 24a of blower 6
compared with the case where no clearance t is provided, thus
extending an effective heat exchange area of the heat exchanger.
This improves heat exchange performance, so that dehumidifying
apparatus 1 having excellent power saving performance can be
provided through improvements in evaporation performance and
condensation performance.
Embodiment 8
[0082] Referring to FIG. 10, dehumidifying apparatus 1 of
Embodiment 8 of the present invention includes a drain pan 18
disposed below condenser 3. Drain pan 18 is configured to store
dehumidification water (drain water). A clearance is provided
between condenser 3 and drain pan 18. In other words, the bottom
surface of condenser 3 and the upper surface of drain pan 18 are
vertically apart from each other. In the present embodiment, also,
fin 11 is provided between adjacent first heat transfer tube 12.
Fin 11 may be a corrugated fin. The clearance between fin 11 or
first heat transfer tube 12 and drain pan 18 may be provided with a
header (not shown) as a pillar.
[0083] In dehumidifying apparatus 1 of the present embodiment, a
clearance is provided between condenser 3 and drain pan 18. This
can reduce pitting of fins 11 and first heat transfer tubes 12 of
condenser 3 due to a potential difference between evaporator 5 and
condenser 3 through dehumidification water.
[0084] When a common heat exchanger of plate fin type is used,
dehumidification water 19 is held by fin 11 at the lower end of
condenser 3. Consequently, dehumidification water 19 flows to a
drain tank less easily, which may lead to leakage of
dehumidification water 19.
[0085] In dehumidifying apparatus 1 of the present embodiment, a
clearance is provided such that fin 11 or first heat transfer tube
12 of condenser 3 does not contact drain pan 18. This restrains fin
11 at the lower end of condenser 3 from holding dehumidification
water 19. This restrains dehumidification water 19 from flowing to
the drain tank (not shown) less easily, thus reducing leakage of
dehumidification water 19.
[0086] It should be understood that the embodiments disclosed
herein are illustrative and non-restrictive in every respect. The
scope of the present invention is defined by the terms of the
claims, rather than the description above, and is intended to
include any modifications within the meaning and scope equivalent
to the terms of the claims.
REFERENCE SIGNS LIST
[0087] 1 dehumidifying apparatus, 2 compressor, 3 condenser, 4
decompressor, 5 evaporator, 6 blower, 10 refrigerant circuit, 12
first heat transfer tube, 14 second heat transfer tube, 18 drain
pan, 20 casing, 24a suction port, t clearance.
* * * * *